This invention relates generally to a spraying system, an associated marking system and a method for using both to spray or coat a surface and more particularly to a spray system for coating or insulating a relatively flat surface, a marking system for defining a grid on the relatively flat surface and a method for using the spray system and the marking system in order to spray coat or foam the relatively flat surface with a desired quantity of material thereby providing a desired finished thickness.
Spray systems for coating roofs with a sealant or other protective coatings are well known. Material manufactured for roof coating has been improved significantly in recent years. As a result, the final thickness of the material can now be measured in mils (one mil=0.001 inch).
The improvement in the material has produced an increase in the cost of the material and a decrease in the tolerance allowed for an acceptable coating. Two of the most common materials now sprayed on roofs, decks and the like are a sprayed polyurethane foam and a sprayed elastomeric coating system. The latter can be used as a base for the former. The increase in cost and decrease in tolerance has created a dilemma for the spray contractor, plant manager and engineer or anyone else responsible for providing or obtaining at least the minimum coating thickness for the lowest price. This dilemma has presented a challenge to the manufacturers of spray equipment as well in that they must meet a challenge to provide increasingly accurate spraying systems in an industry that relies, and has relied for years, almost entirely on the skill of a sprayer to lay down the desired thickness of a material and no more.
It is known to mark off an area of several hundred square feet (or squares) and then spray the area. The amount of coating is then checked (by either measuring the thickness of the coating or the amount of material sprayed since by simple arithematic the coating thickness per area can be used to calculate the amount of material it takes, for example, in gallons or gallons per square) for accuracy. The spray gun operator has only his experience to determine the approximate amount of coating to be applied. If too much material was sprayed, then the operator attempts to spray less on the next section tested, if in fact it is tested again. Testing a sample square footage is inaccurate due to measurements of the material sprayed. Ultimately, the operator relies almost totally on experience and skill to spray the correct amount (thickness) on the surface to be coated.
The ability of a spray operator to apply a coating in a proper thickness can be affected by a number of factors. The following are just a few of the factors affecting the finished coating thickness. The viscosity of the material can vary from drum to drum. The viscosity can also vary with ambient temperature. Viscosity variations are difficult for the spray operator to detect in order to adjust the spray pattern. Spray operator fatigue, adverse ambient conditions, and time of day can all affect the spray operator's judgment as to how much coating is being applied.
A spray hose supplying the material is typically controlled by a helper, a "hose person". The hose person is responsible for managing the hose to keep it out of the spray operator's way. The hose person can affect the amount of coating sprayed in a number of ways. For example, too much or too little tension on a hose will either pull the spray operator backwards across the surface too quickly or too slowly as the spray operator waits for the hose to be pulled back. Both the speed of movement and spray width have been found to be affected by the actions of the hose person.
Accordingly, it is an object of the present invention to provide a spray system and method including spray apparatus and marking apparatus and a method for using the apparatus.
It is another object of the present invention to provide an apparatus and method that enables a spray operator to accurately spray a desired amount of material to a desired area of a roof or other surface.
It is another object of the present invention to provide an apparatus and method for applying a grid to a surface to be sprayed and coated. The grid effectively divides the roof into small segments. The grid marks off a lane for the spray operator and provides means for regulating the speed of the spray operator and back and forth spraying action.
It is another object of the present invention to provide an apparatus and method that provides a tighter control on the cost of a spray or coating project. The coating thickness is controlled, thereby keeping the spray operator from spraying extra material "just in case" which increases the cost of materials.
It is another object of the present invention to provide an apparatus and method that reduces or eliminates the need to re-coat a surface, thereby increasing the cost of the spray or coating project. If too little material is sprayed and the coating thickness does not meet the minimum specified thickness, then the cost of re-spraying includes quite often both another primer coat and a finished coat.
It is another object of the present invention to provide an apparatus and method that effectively links the spray operator with a ground crew and the equipment located on the ground or otherwise remote from the spray operator.
It is another object of the present invention to provide an apparatus and method that can provide an evenly sprayed coating with no thick or thin spots. The even coating results in part from the substantially uniform passes that a spray operator can make with the spray equipment by using a grid pattern defining lanes to guide the spraying.
It is another object of the present invention to provide an apparatus and method that can be readily used to spray foam (e.g., foam insulation) with a tapered thickness.
It is another object of the present invention to provide an apparatus and method that can be readily used by a number of spray operators without a resulting variation in thickness due to the particular style of the spray operators. The apparatus and method of the present invention further provides for a reduction of stress to the spray operator. The grid relieves a significant portion of the tension associated with the task of applying the proper thickness of the coating or foam material. The present invention provides for the use of spray operators regardless of skill or experience.